CVE-2023-52558 in OpenBSD
Summary
by MITRE • 03/01/2024
In OpenBSD 7.4 before errata 002 and OpenBSD 7.3 before errata 019, a network buffer that had to be split at certain length that could crash the kernel after receiving specially crafted escape sequences.
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Analysis
by VulDB Data Team • 11/20/2024
The vulnerability identified as CVE-2023-52558 represents a critical kernel-level issue affecting OpenBSD versions 7.4 prior to errata 002 and 7.3 prior to errata 019. This flaw manifests within the network subsystem where specific buffer handling operations can lead to system crashes when processing specially crafted escape sequences. The vulnerability stems from inadequate boundary checking and memory management during network packet processing, particularly when dealing with buffer fragmentation scenarios that require splitting network buffers at specific lengths.
The technical implementation of this vulnerability involves the kernel's network buffer management system failing to properly validate input sequences that contain escape characters or special control codes. When the network stack encounters these crafted sequences, it attempts to split network buffers at predetermined lengths, triggering a memory corruption condition that results in kernel panic and system crash. This behavior aligns with CWE-129, which addresses improper validation of buffer boundaries, and specifically relates to improper handling of input validation during buffer operations. The flaw demonstrates characteristics consistent with buffer overflow conditions where the kernel's memory management routines fail to account for edge cases in packet processing.
From an operational perspective, this vulnerability presents significant risk to systems running affected OpenBSD versions as it allows remote attackers to cause denial of service through carefully constructed network traffic. The impact extends beyond simple service disruption since kernel crashes can result in complete system downtime and potential data loss. Network administrators must consider the possibility of automated exploitation where attackers could repeatedly send malformed packets to maintain persistent denial of service conditions. The vulnerability's classification under the ATT&CK framework would fall under T1499.004 for Network Denial of Service, and potentially T1059.007 for command and control through network protocols.
Mitigation strategies for CVE-2023-52558 require immediate application of the respective errata patches provided by OpenBSD security team. System administrators should prioritize updating affected systems to OpenBSD 7.4 errata 002 or 7.3 errata 019, which contain the necessary kernel fixes for proper buffer handling and escape sequence validation. Network-level mitigations include implementing firewall rules to filter suspicious network traffic patterns and monitoring for unusual packet fragmentation behaviors. Additionally, organizations should conduct thorough vulnerability assessments to identify systems running affected OpenBSD versions and establish incident response procedures for potential exploitation attempts. The fix addresses the root cause by implementing proper buffer boundary validation and ensuring that network buffer splitting operations handle escape sequences safely without corrupting kernel memory structures.